6.5 grendel 180?

[beltfed]

Rifle length gas isn't about higher velocities, it is about softer, more manageable recoil and reduced pressures and strain on the rifle.

This is plainly evident on a .223 rifle, 6.5 Grendel even more so.

If you went with mid length for a barrel that is measuring 18.5" or greater, you are compromising pure and simple.

 

[the radium king]

you are also compromising by carrying around that heavy barrel. you can reduce recoil and pressures by reducing the amount of gas that gets redirected. and i noted the concept of timing the action with gas length in my previous post.

 

[Ustauk]

Just a note, Crusade Arms/Spectre Ltd. confirmed on Instagram that their new Sentinel 5.56 platform can accept a 7.62x39mm MCR bolt in its BCG, which should also work for the Grendel. The platform uses a mid-length piston that is thicker then the MCR or WK's. The monolithic hand guard in concert with the more robust gas system makes for a thicc firearm, but with a barrel and bolt swap it may make for a nice Grendel host.

 

[the radium king]

well, i'm enroute to becoming another date point. i've got an rwa 7.62x39 upper (stuck w mid-length gas system and their bolt i think) so ordered an ibi 6.5g hb 8 twist barrel at 0.125" and mid-length gas. intent is to burn cheap 7.62x39 and just swap barrels to go hunting with the 6.5g. i'll report back after everything shows up, weather warms up, and i can get a few rounds downrange. ps, i've been working with jerry at mystic precision to get the barrel and he's been excellent to work with as i've modified my order several times ...

right - update. the rifle is a treat. soft shooting, runs flawlessly. it seems accurate - 2 moa with cheap federal fmj while just trying to get it onto the paper at 100 yds. using a sightmark wraith so lots working against me there (digital zoom, lag, etc.). 0.076" gas port at mid-length provides just the right amount of gas, and a tna recoil buffer is the final piece of the puzzle (they sent two when i ordered; one sized for 9mm and one for the bigger guns). shoots softer than when gun was in 7.62x39 format and seems similar to my hk in 223 (also 180-style).

feed ramps required a lot of work out of the box, but working well with cpd lar 7.62x39 mags (still holds 10). and the lynx lower is a nice piece but was a LOT of work; fitting the bolt hold-open, fitting the safety, fitting the mag release, and fitting the trigger (hammer was hitting the webbing in the lower and not contacting the bcg). have to run a mil-spec trigger to detonate the primers; triggertech competition couldn't do the job.

gun is heavy but balance isn't too bad; i thing the H-bar profile moves the weight back more to the centre of the gun. i think this is going to make a great hunting gun, although still need to sort out how to keep the crud out of the receiver.

 

[Ustauk]

Thanks for to the info! I will pass the info on to the Crusader guys; they were wondering if there would be interest in other calibres for their new Templar platform, and it maintains a mod length gas system from the Sentinel, so your info could be useful.

 

[the radium king]

np. i'm a fan of the grendel; shoots a good bullet, carries lots of powder but doesn't beat you up, easy to reload. about as close as i'm going to get to a m305 replacement at this point.

there is the type i vs type ii debate and i've not enough rounds downrange to speak to the longevity of the thinner extractor and lugs on my x39 bolt face, but i carry a spare extractor and can swap in under a minute if needed. 6.5 is a bit too pricy to shoot in 3-gun, etc., so this is a hunting gun that won't see a lot of rounds. i've got a galil ace dust cover on order to see if i can sort out the charging handle gap.

 

[rugbydave]

np. i'm a fan of the grendel; shoots a good bullet, carries lots of powder but doesn't beat you up, easy to reload. about as close as i'm going to get to a m305 replacement at this point.

there is the type i vs type ii debate and i've not enough rounds downrange to speak to the longevity of the thinner extractor and lugs on my x39 bolt face, but i carry a spare extractor and can swap in under a minute if needed. 6.5 is a bit too pricy to shoot in 3-gun, etc., so this is a hunting gun that won't see a lot of rounds. i've got a galil ace dust cover on order to see if i can sort out the charging handle gap.

I'm glad it's working well for you! I'd really like to do one of these, preferably on a Templar/Sentinel upper since it's enclosed. Curious to hear how you make out with the Galil Ace dust cover on the open upper. Might work on WK and WS' as well?

I'm also curious to see how the bolt holds up for you. I've been debating whether to do this project as a type 1 with a x39 bolt or type 2 with TNA's 6.5G bolt (which isn't surface treated).

Regardless, I think it would be rad to have an accurate, enclosed, semi-auto 6.5G for hunting and plinking.

 

[romayama]

Has anyone built a 6.5 Grendel Wk180/MCR? Building a shorty 11.5 180 for the range, but I also want to build an SPR style rifle, ideally in 6.5 grendel if it can be done.

I happened to build one, it was functioning well, although aesthetics of the 180 lower are not for everyone . It was more difficult than I imagined. Sold it later to fund a new project, it is up for grabs by the new owner now on GP. Videos below show the gas system testing. It required custom gas system machining (inspired by the SVT-40), the rifle would not cycle with the 180 factory tiny piston otherwise. Oversize outrider piston created a handguard clearance issue which required switching to the Magpul handguard.

That all being said, I believe Templar is a great platform for all kinds of conversions - factory large piston diameter, tons of handguard clearance for any kind of custom gas blocks. Good for 6.5 Grendel, 6mm ARC, 300 Blackout, 7.62x39.

View attachment 615978
View attachment 615979

 

[Hornychief]

Interested in more range trips feedback and pics

 

[Sqr]

You need the x39 bolt, a barrel and Grendel mags. Probably a longer op-rod, i don't think a carbine Grendel barrel exists. From there it should be fairly straight forward. The only gotcha i have found with using AR barrels on the MCR was the gas hole needed to be opened up a bit. At which point an adjustable gas block is handy in case you go too far or need to tune for your load.

If you go 7.62 bolt then using 7.62 brass is a must for correct head-spacing.

 

[romayama]

If you go 7.62 bolt then using 7.62 brass is a must for correct head-spacing.

True. In my case headspace was off out of the box - too short, bolt did not close on the Hornady factory casing. Had to shave the locking lugs in a lathe a few thou, to make headspace work - something to be prepared for, just in case.
I takes the same amount of time and effort to build a T81 or SKS in 6.5 Grendel

 

[the radium king]

True. In my case headspace was off out of the box - too short, bolt did not close on the Hornady factory casing. Had to shave the locking lugs in a lathe a few thou, to make headspace work - something to be prepared for, just in case.
I takes the same amount of time and effort to build a T81 or SKS in 6.5 Grendel

were you using the proper bolt/barrel combination? the contemporary grendel headspace/chamber depth is for a grendel bolt with a 0.136" bolt face recess. you can use a standard 7.62x39 bolt but have to ensure you ream the chamber 0.011" deeper to address the fact that the 7.62x39 bolt face s only 0.125" deep. otherwise the bolt won't lock (brass sticking out too far). if, instead of reming the chamber deeper or increasing the bolt face depth, you "shave the locking lugs" then you have 0.011" of exposed brass on a round that is running 52,00 psi. probably not a big deal but sounds like a bit of a time bomb to me.

 

[romayama]

Thanks for the comment. Reaming the nitride-treated chamber would be hard, if not impossible, that is why I chose the other way. Had to remove no more than 0.005" from the lugs and bolt was not 7.62x39. The brass is seated in fully with a tight headspace; fired brass is shaped as it should, no rings or bulges.
As for the practical pressure - eventually I shot a few slightly dented casings of 6.5 through my bolt action - there was not enough pressure to straighten those dents, which truly surprised me. Loads were in the middle, between the min and the max values

 

[Brando4162]

I had a first gen 180 in 6.5 grendel, it constantly had failure to feed and extract issues with barnaul ammo, it ran decently well with hornady brass but it was to expensive for me.

 

[romayama]

I had a first gen 180 in 6.5 grendel, it constantly had failure to feed and extract issues with barnaul ammo, it ran decently well with hornady brass but it was to expensive for me.

Typical for the AR barrel/chamber design, inherently unfixable unfortunately.

 

[the radium king]

my first gen grendel runs fine on american eagle. you can't just slap a barrel in a gun and expect it to run; mine took some work on the feed ramps to get it to feed reliably. i've not had any extraction issues but suspect quality of barrel is a thing; you need a really smooth chamber to keep the straight-walled, overstuffed 6.5 from sticking. my ibi is flawless in that respect. the cost of feeding it is an issue, but becoming one for all calibers unfortunately. reloading was the solution as 6.5 bullets are common, but primers are difficult to find these days.